1. Technical Field
This technology pertains generally to piezoelectric oscillators, more particularly to switched piezoelectric oscillators, and still more particularly to piezoelectric oscillators with a variable Q.
2. Background Discussion
Conventionally, micromechanical switches must be disposed along the signal path to attached electrode AlN resonators in order to switch such resonators on or off. Such switches have associated insertion losses, tend to increase part count, and decrease overall system reliability.
If the resonators to be switched are hooked in a parallel bank, the use of series switches either before or after each resonator leads to changes in input or output capacitance, respectively, when different sets of resonators are turned on and off. This makes impedance matching to adjacent stages a dynamic problem, and more difficult to solve.